Apparatus for producing low carbon iron



APPARATUS FOR PRODUCING LOW CARBON I-RON Filed Nov. 28, 1928 Figi.

Inven'or' Irving R. valentin@ bg Hi s AlTonneH.

Patented Aug. 4, 1931 UNITED STATES PATENT oFFlcE IBV'ING B. VALENTINE, 0F ERIE, PENNSYLVANIA, ASSIGNOB TO GENERAL ELECTRIC COMPANY, A CORPORATION 0F NEW YORK APPARATUS FOB PROD'UOING LOW CARBON IRON Application filed November 28, 1928. Serial No. 322,581.

The present invention relates to means for reducing low carbon or perlitic cast iron 1n a cupola furnace. While perlitic iron has been produced heretofore, it has been a customary in the production of such iron to regulate its carbon content by some means external to the cupola in' which the iron was melted, such for example as a forehearth or externally heated furnace, or by preheated molds into which the iron was cast.

It is one of the objects of the present invention to produce in a cupola melting furnace cast iron having a low carbon content and perlitic structure.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. The invention itselfhowever will best be understood from reference to the following 0 specification. when considered in connection with the accompanying drawings in which Fig. 1 shows diagranunatically a cross section of a cupola melting furnace embodying the features of the present invention, while Fig. 2 is a cross section of the furnace taken on line 2-2 of Fig. 1.

Referring more particularly to the drawings, I have indicated at 1 a cupola meltin furnace which comprises a metal casing 2 lined with fire brick 3 1and having a' hinged metallic base plate 4 held in closed position by an iron post 5. The furnace 1 is of the ordinary cupola type and is provided with the usual wind boxes 6 and 7, tuyres 8 and 9, slag hole 10 and tap hole 11. A brick wall 12 serves to support the cupola. The base plate 4 of the furnace is covered with a layer ofsand 13 providing a hearth on which fire 'brick 14 'or other suitable refractory material is laid so as to support a layer 15l of lsolid fuel such as coke or other carbonaceous material out of contact with the sand layer 13 and provide a space or reservoir 16 into which molten iron may coke layer 15. It is desirable to extend the iire brick 14 about up to the slag hole 10.

In operation, the brickwork 3 and the lower coke bed 15 are heated by an oil burner or other suitable means until the bricks settle and be held out of lcontact with'the l work is red hot. The blast is then put on sulciently to light the coke, and the cupola charged in the usual manner with alternate layers of coke and iron as indicated at 15 and 17 on the drawings. As the iron melts it flows through the coke bed 15 and into the space or reservoir 16 in the base portion of the cupola and between the coke bed and the sand layer 13. In this manner the molten iron is in contact with the coke l15 for a very short period of time and the amount of carbon thus taken up by the molten iron is very small.

From a charge containing 30% scrap, 40% steel and 30% pig iron, castings have been obtained which have a tensile strength of about 45,000 pounds per square inch and a Brinell hardness of 228, the content of the iron being substantially as follows:

Per nt Carbon 2.92 Silicon 1.39 Phosphorus .40 ManganeseV i .40 Sulphur .14 Iron.v Remainder In normal -Ycupola operation the above charge would give iron having a tensile strength of approximately 32,000 pounds per square inch, a Brinell hardness of 180, a carbon content of 3.60% and a silicon content of 1.40%.

Although I have employed fire brick, placed loosely in the bas'e of the cupola to hold the coke bed out of contact with the sand layer and thereby provide a space in which the molten iron may be held outl of contact with thercoke bed, it will be clear that other constructions adapted to support or bridge the coke bed and. permit the molten iron to How therethrough may be employed if desired. Although it is ossible with the lari'angement shown to pro uce iron having a carbon content varying from '.2 to 3%, this content may be further reduced if desired by blowingv air through the molten iron in the cupola.

What I claim as new and desire to secure by Letters Patent of the United States, is: 1. A cupola melting furnace employing solid carbonaceous fuel to melt the charge, said furnace comprising a hearth, refractory means mounted on said hearth and adapted to support said carbonaceous fuel 5 out of Contact with the molten metal, and means for supplying a blast of air to said carbonaceous fuel.

2. A cupola melting furnace provided with a hearth portion and having a slag hole 10 adjacent said hearth, and refractory means mounted in the furnace below said slag hole for supporting solid carbonaceous fuel and the metal to be melted, out of contact with the molten metal and means for supplying i5 a blast of air to said carbonaceous fuel.

3. A cupola melting furnace having a hearth portion and a slag hole adjacent said hearth, refractory means mounted on said hearth and extending upwardly to a point 20 adjacent said slag hole to support a charge of solid fuel and iron in the furnace and to provide a reservoir for the molten metal out of contact with said fuel.

In witness whereof, I have hereunto set 25 my hand this 26th day of November, 1928. RVNG R. VALENTINE. 

